137Cs and 40K concentration ratios (CRs) in annual and perennial plants in the Caspian coast

Abstract

This research attempted to investigate the plant/soil concentration ratios (CRs) of 137Cs and 40K in plants that grow on the Anzali Lagoon of the Caspian coast, Iran. The activity concentrations of 137Cs and 40K were measured in soil samples, annual plants (Echinochloa crus-galli, Digitaria sanguinalis, and Trifolium repens), and perennial plants (Phragmites australis, and Cynodon dactylon). The relationship of activity concentration with soil particle density, and pH of soil samples, CR, and 137Cs/40K discrimination factor (DF) were determined. The activity concentration of 137Cs in the soil, annual plants, and perennial plants ranged between 12- and 124 (Bq/kg dry weight), 2- and 17 (Bq/kg dw), and 2 - and 14 (Bq/kg dw), respectively. The geometric mean (GM) values of DF in annual and perennial plants were 0.57 and 0.55, respectively. The CR for 137Cs and 40K varied as a non-linear relation in annual plants and perennial plants. This study showed that the CRs for 137Cs in annual plants were higher than the CRs for perennial plants.